If you find an error, please let me know:

Chapter 1

Page 5 (Electronic and Print)

Current greetUser() function is missing a closing paren in the arguments. The fixed version:

func greetUser(c config, name string, w io.Writer) {
        // function body remains same

(Thanks to Max Wolffe for reporting)

Listing 1.1

The function definition of validateArgs() should check that, the user hasn’t specified the -h flag.

Reported as a GitHub issue and fixed by titoe218.

(Thanks titoe218 and daniel-lee-tech)

Chapter 3

Page 79 (Electronic and Print)

Listing 3.9, the call to registerPackageData() function is missing the second argument.

The published code is correct, and you can find it here.

Reported as a GitHub issue.

(Thanks rikyhidayat21)

Chapter 7

There is a bug in Listing 7.5 described in detail here.

The fixed code is available in the v1.0.2 release.

(Thanks joergjo)